As a power conversion device, there is known a matrix converter that includes a plurality of bidirectional switches that connects each input phase to each output phase. A technology for realizing the step-up function of the matrix converter has been known as disclosed in, for example, WO2006/112275.
The matrix converter having a step-up function includes electric reactors between each phase and the bidirectional switches. The matrix converter short-circuits the input-phase-side electric reactor and then releases the reactor from the short circuit by using the bidirectional switches to output a voltage higher than a supply voltage.
However, because the conventional matrix converter having a step-up function includes electric reactors, capacitors, and connection/disconnection means at both sides of input and output, there is a problem that the device should be large-sized.